Tow tractor



FIG. 1 is a front, top and left side perspective view of a tow tractor showing my new design;

FIG. 2 is a rear, top and right side perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a left side view thereof.

The bottom plan view is omitted since it is unornamented and forms no part of the claimed design. The oblique shade lines shown in the drawings indicate a transparent or translucent surface. 

CLAIM The ornamental design for a tow tractor, as shown and described. 